Technical Field
Embodiments of the present disclosure relate to a communication terminal, a communication system, and a data transmission method.
Background Art
With the need for reducing costs or times associated with business trips, communication systems are widely used, which are capable of carrying out videoconferences among remotely located sites through a communication network such as the Internet. When communication among a plurality of communication terminals is started, such communication systems exchange contents of data such as image data and audio data with each other. Accordingly, the communication among the participants who use the communication terminals is realized.
For example, an integrated presence management system is known that includes a communication terminal with a memory or the like in which a plurality of application client programs are stored and a presence server with a memory or the like in which presence information of the communication terminal is stored. When a request to register the presence information of one of the multiple applications of the above communication terminal is received from the communication terminal, the presence server synchronizes the presence information of at least one another application of the above communication terminal, which belongs to the same group as the one of the multiple application of the above communication terminal, with the one of the multiple application of the above communication terminal.
As methods for notifying a counterpart communication terminal of the disconnected communication at a communication terminal, a method is used in which information such as a heart-beat packet is sent, at a prescribed timing, from the communication terminal to a management system that manages the communication. In such a method, the management system notifies the counterpart communication terminal of the disconnected communication at the communication terminal when the information such as a heart-beat packet is no longer sent from the communication terminal. However, when a plurality of communication applications operates in the communication terminal and each of the communication applications sends such information as above to the management system, the load on the communication network increases.